Touch Me Not plant got this name from its super sensitivity to touch. When the plant detects touch from any foreign object, the leaves fold and bow as if it is shy. Its Malayalam name is Thottavadi, which also denotes this peculiarity. Shameplant is another common name in English.
Thottavadi belongs to the family Mimosaceae and its scientific name is Mimosa pudica. It has several uses in traditional medicines in many parts of India.
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Plant Type: Annual or Perennial Herb/Creeper
Scientific name: Mimosa pudica
Appearance: grows up to half a meter height,
spreads on the ground with a thorny stem
Flowers: pink, spherical
Leaves: Bi-pinnate with around 20 pairs of touch-sensitive leaflets
Distribution: widely distributed in tropical areas including India, native to South & Central America
Sanskrit: Lajjalu, Rakthapadi
English: Touch-Me-Not Plant, Shameplant
Main uses: Traditional medicines & ornamental
Mimosa pudica is a thorny creeper that grows by spreading on the ground. The stem has numerous branches and sub-branches.
The pinnate leaves have around 20 pairs of leaflets which can fold in response to even the slightest movement or touch. It opens and regains the shape after a couple of minutes. The leaf is 2 to 5cm in length.
The flower cluster is spherical in shape, which is highly attractive. Its color is light pink.
The herb grows to about 50cm from the ground and can spread on an area creating a thorny carpet on the ground spanning a few meters.
Basically, chemical changes resulting from physical stimuli are the reason behind M.pudica’s folding leaves. Many other species from this family also exhibit this behavior known as Thigmonasty.
The leaflets of the Touch Me Not plant stay erect due to water pressure. When stimulated, water flows out of the leaflet resulting in a loss of pressure. Hence the leaflets fold and bow down. There are also ion movements and chemical changes associated with this movement.
When someone touches the tip of a leaf, the touched leaflet is not the only one that limps down. The stimulus can traverse the whole length of the leaf resulting in leaflets folding one by one from the tip to the base.
Touch Me Not plant is native to South America although it is now widely found in places like India. In India, it grows well on plains along roadsides and open lands.
It does not require very fertile soil but prefers a warm and sunny climate with a good amount of rainfall.
The use of Mimosa pudica has been prevalent in traditional health care systems in India. According to Ayurveda, the plant may be used to cure skin allergies and asthma[ref].
The parts of this plant exhibit antibacterial properties since it contains several compounds like tannins, terpenoids, and glycosides. It is also said that M.pudica has anti-diabetic properties in addition to the ability to heal wounds and reduce toothache[ref].
Although a weed in many parts of the world, Mimosa pudica has certain environmental significance as it can improve the quality of soil by fixing nitrogen[ref].
Apart from all these, the folding leaves and pink flowers make it an attractive ornamental plant also.